1. Field of the Invention
The present invention relates to an image processor, an image processing method and a storage medium storing a control program thereof, which are applicable to, for example, a combined copying machine having a high-speed image memory (RAM) and a bulk image memory (Hard disk device: hereinafter referred to as HD).
2. Related Background Art
As generally known, image processors such as combined copying machines must process image data that are read at high speed from scanners and the like. Thus, input image data are stored in a RAM that can be accessed quickly, thereby keeping up with the speed of scanners. Similarly, for output sides, output image data are stored in the RAM, and image data are supplied therefrom to a printer for keeping up with the print speed of the printer.
Furthermore, for a plurality of copies of a manuscript, there has been proposed a technique in which using a HD as a bulk image memory, image data read by a scanner is first stored in the RAM, and is transferred to the HD on a temporary basis, and the image data required for the printer is transferred from the HD to the RAM, and is outputted to the printer, and in this manner the required number of copies are created by reading the manuscript only once.
However, the described technique has a disadvantage in that the FCOT (First Copy On Time; see below), considered as being important for the copying machine, is prolonged because the HD cannot be operated at high speed.
The FCOT referred to is a time interval between the time when a start key of the copying machine is depressed and the time when the first copy is obtained. For example, the RAM that is used for input can be used also as the output RAM, thereby making it possible to speed up the FCOT for only one copy, but for dealing with a plurality of copies of multiple pages, a large-volume RAM is required.
However, RAM is very expensive compared to a HD having the same capacity, and is not practically suitable for commercial production. In a different way, if everything is dealt with using a high-speed HD (such as a RAID), there is a disadvantage in that such a HD is also very expensive.
Furthermore, it can be considered that these conditions will be increasingly strict and the described problem will be larger in the future, due to the enhanced speed and resolution of scanners and printers.
Furthermore, this problem has been described using the copying machine as an example, but it can be considered that in reality, due to complex operations with a facsimile machine and other networks, one input image is supplied to a plurality of output units, and not only to copying machines.
Also, the described problem holds true not only for the copying machine but also for the facsimile machine, a PDL board (printer) and so on. However, the relevant constraints on time and speed are most severe for the copying machine.